Amanita pseudosychnopyramis Yang Y. Cui, Qing Cai & Zhu L. Yang.
Index Fungorum number: IF551334; Facesoffungi number: FoF00897; Figs. 1, 2, 3 and 4
Etymology – pseudosychnopyramis, named due to its similarity to A. sychnopyramis.
Holotype – HKAS 87999
Basidiomata small to medium-sized. Pileus 4 – 7 cm in diam., plano-convex to plane, often slightly depressed at center, at first yellow (3A4 – 8) over disk, then yellowish brown (3B2 – 8) to brownish (3C4 – 7) at center, becoming yellowish (3A2 – 3, 3B2 – 4) to dirty white (3B1 – 2) toward margin, viscid when moist; margin tuberculate – striate (0.25 – 0.3R), nonappendiculate; volval remnants as conical, subconical to pyramid, dirty white to grayish (3B1 – 2) to brownish grey (3A2 – 4; 3B2 – 3), randomly arranged, small warts; trama white (1A1), unchanging. Lamellae free, white (1A1), crowded; lamellulae truncate, plentiful, evenly distributed. Stipe 6 – 8.5 × 0.3 – 0.8 cm, subcylindric or slightly tapering upward, with apex slightly expanded, dirty white (3A1 – 3) to yellowish brown (4A2–3, much paler than 4B2 – 3), subglabrous or covered with white (1A1) floccose squamules; context white, hollow in center; basal bulb subglobose to long ellipsoid, 1 – 1.3 cm in diam., white (1A1) to dirty white (3A1 – 3), upper part covered with conical to subconical to granular grayish to brownish grey volval remnants arranged in several incomplete rings, usually forming a short limbate collar between the stipe and the bulb. Annulus present, superior, pendant from attachment 2–3 cm below apex of stipe, white (1A1), thin, membranous, fragile. Odour indistinct.
Lamellar trama bilateral. Mediostratum 40 – 75 μm wide, composed of abundant subglobose, ellipsoid to long ellipsoid inflated cells (35 – 110 × 25 – 50 μm); filamentous hyphae abundant, 2 – 8 μm wide; vascular hyphae rare. Lateral stratum composed of abundant ellipsoid to long ellipsoid inflated cells (25 – 70 × 7 – 17 μm), diverging at an angle of ca. 30 – 45° to the mediostratum; filamentous hyphae abundant, 3 – 5 μm wide; septa without clamps. Subhymenium 35 – 70 μm thick, with 2 – 3 layers of subglobose, ellipsoid or irregularly shaped cells, 7 – 30 × 12 – 25 μm. Basidia 36 – 47 × 10 – 13 μm, clavate, 4 – spored, sometimes 2 – spored; sterigemata 3 – 4 μm long; basal septa without clamps. Basidiospores [140/7/3] (7–)8 – 10(−11.5) × (6.5–)7 – 8.5(−10.5) μm [Q=1.06 – 1.20(1.39), Qm=1.13 ± 0.05], subglobose to broadly ellipsoid, inamyloid, colourless, hyaline, thin-walled, smooth; apiculus small. Lamellar edge appearing as sterile strip, composed of subglobose to ellipsoid inflated cells (9 – 25 × 7 – 15 μm), single and terminal or two in chain and then terminal, thin-walled, colourless, hyaline; filamentous hyphae abundant, 2 – 4 μm wide, irregularly arranged or ± running parallel to lamellar edge. Pileipellis 150 – 200 μm; upper layer (60 – 80 μm thick) strongly gelatinized, composed of radically to subradically, thin-walled, colourless to nearly colourless, filamentous hyphae 2 – 7 μm wide; lower layer (80 – 125 μm thick) composed of compactly arranged, filamentous hyphae 3 – 8 μm wide; vascular hyphae rare. Volval remnants on pileus composed of more or less vertically arranged elements; inflated cells very abundant to nearly dominant, subglobose to ellipsoid (18 – 70 × 15 – 50 μm), in chains of 2 – 3 and then terminal, thin- to slightly thick-walled, yellowish to brownish vacuolarly pigmented, sometimes nearly colourless; filamentous hyphae abundant, 3 – 11 μm wide, thin – walled, yellowish to brownish vacuolarly pigmented or nearly colourless; vascular hyphae rare. Volval remnants on the stipe base (outer surface of the limbate collar) composed of somewhat irregularly arranged elements; inflated cells very abundant, subglobose to ellipsoid (22 – 100 × 15 – 45 μm), thin – to slightly thick – walled, in chains of 2; filamentous hyphae abundant, 3 – 8 μm wide, colourless to nearly colourless, thin-walled; vascular hyphae rare; interior of limbate collar on the stipe base composed of very abundant to nearly dominant filamentous hyphae 3 – 8 μm wide, mixed with scattered inflated cells; inner surface of limbate collar gelatinized, composed of filamentous hyphae 3–6 μm wide. Stipe trama composed of longitudinally arranged, long clavate, terminal cells, 200 – 450 × 25 – 50 μm; filamentous hyphae scattered (in interior) to fairly abundant (on stipe surface), 5 – 18 μm wide; vascular hyphae rare. Annulus composed of loosely and irregularly arranged elements; inflated cells abundant, ellipsoid to long ellipsoid to clavate (28 – 95 × 15 – 35 μm), colourless to nearly colourless, thin – walled, single and terminal or in chains of 2 – 3 and then terminal; filamentous hyphae abundant to very abundant, 3 – 7 (−10) μm wide, colourless to nearly colourless, thin – walled; vascular hyphae rare. Clamps absent in all parts of basidioma.
Habitat and distribution: Solitary or gregarious in southern subtropical forests of Fagaceae. Distributed in southweatern and southern China.
Material examined – CHINA, Guangdong Province, Fengkai County, Heishiding, Fagaceae (altitude 500 m), 20 March 2012, F. Li 66 (HKAS 78417); the same location, Fagaceae (altitude 320 m), 16 March 2014, F. Li 1593 (HKAS 82293); Yunnan Province, Jinghong City, Dadugang Township, Fagaceae (altitude ca. 1000 m), 30 June 2014, K. Zhao 467 (HKAS 87999, holotype!).
Notes – Amanita pseudosychnopyramis is characterized by its conical to pyramid grey to brownish grey volval remnants on the pileus, a basal bulb with a short limbate collar and its subglobose to broadly ellipsoid basidiospores (8.5 – 10 × 7.5 – 8.5 μm). It is associated with subtropical forests dominated by Fagaceae.
Amanita pseudosychnopyramis resembles A. sychnopyramis f. sychnopyramis and f. subannulata, by its small to medium-sized basidiomata, characterized by a brownish to brown pileus with grey to brownish grey, conical to pyramid volval remnants. However, A. sychnopyramis f. sychnopyramis and f. subannulata has usually a bulb with conical to granular volval remnants arranged in incomplete rings, smaller basidia and smaller basidiospores (Corner and Bas 1962; Hongo 1971; Yang 1997) . Amanita pseudosychnopyramis is also similar to A. parvipantherina, and A. subparvipantherina by its small to medium-sized basidiomata, characterized by a brownish to brown pileus with grey to brownish grey, conical to pyramid volval remnants. Amanita parvipantherina possesses a subglobose basal bulb, with floccose to granular volval remnants which usually do not form a limbate volva on the base of the stipe and broadly ellipsoid to ellipsoid basidiospores (8.5 – 11.5 × 6.5 – 8.5 μm) (Yang et al. 2004; Yang 2005, 2015). Furthermore, it occurs in mixed forests with pine trees. Amanita subparvipantherina has a short limbate collar volval remnants on the stipe base, broadly ellipsoid to ellipsoid basidiospores (9 – 11.5 × 6.5 – 8.5 μm), and volval remnants on the pileus with more abundant filamentous hyphae. In our molecular analyses, A. pseudosychnopyramis is supported to be a distinct species and is distantly related to A. parvipantherina, A. subparvipantherina, A. sychnopyramis f. sychnopyramis and f. subannulata (Fig. 1).
Fig. 1 Phylogram of Amanita sect. Amanita generated from Maximum likelihood (RAxML) analysis of LSU, rpb2 and tef1-α sequence data. Maximum likelihood bootstrap values greater than 50 % and Bayesian posterior probabilities over 0.90 are indicated above or below the nodes. The new species are indicated in blue, and the type collections of the species are in bold. The tree is rooted with two species of A. sect. Caesareae, namely A. caesarea and A. jacksonii.
Fig. 2 Basidiomata of Amanita pseudosychnopyramis (HKAS 87999, holotype). Scale bars = 1 cm.
Fig. 3 Microscopic features of Amanita pseudosychnopyramis (HKAS 87999, holotype): a Hymenium and subhymenium; b Basidiospores. Scale bars = 10 μm.
Fig. 4 Longitudinal section of a volval remnant on the pileus from Amanita pseudosychnopyramis (holotype). Scale bars = 20 μm.